EP0578531B1 - Distributed storage non-interruptable power supply system - Google Patents

Description

TECHNICAL AREA

The present invention relates to a power supply system with distributed storage without interruption.

The field of the invention is that of the power supply of telecommunications systems or electronic systems with sensitive operation, that is to say which do not tolerate cuts.

• aux techniques de conversion de l'énergie électrique telles la transformation du courant continu en courant alternatif et la transformation inverse du courant alternatif en courant continu,
• aux techniques de stockage de l'énergie électrique, en mettant en application les récents développements technologiques du domaine,
• à l'association judicieuse de ces différentes techniques et technologies.

The system of the invention is particularly applicable:

• electrical energy conversion techniques such as the transformation of direct current into alternating current and the reverse transformation of alternating current into direct current,
• electrical energy storage techniques, applying recent technological developments in the field,
• the judicious association of these different techniques and technologies.

STATE OF THE PRIOR ART

As described in two articles by J. Girard entitled "Géode, a new concept of the energy supply of telecommunications systems (" Echo of research ", n ° 113, 3rd quarter 1983, pages 45 to 60) and" Geode: a new generation of power plant for telecommunications facilities "(" Commutation and transmission ", number 4, 1986), prior art telecommunications systems, such as that shown in FIG. 1, are supplied with direct current at nominal voltage from 48 V. From the public electrical power distribution network 10 or from a backup source 11 producing an equivalent voltage (230/400 V alternating voltage), a low-voltage switchboard 12 delivers a 400-volt three-phase voltage, which after distribution is received by the system 13 to be supplied comprising rectifiers 14 and 14 ', an accumulator battery 15, and converters 16 and 16'. A conversion is carried out so as to produce a direct voltage of 48 volts, ensuring both the supply of the system 13 and the recharging of the battery 15. The latter supplies the system, during an interruption of the alternating voltage, during the time required for the standby source to operate. The 48-volt voltage is distributed throughout the system to be supplied 13 and converted into several lower voltages, compatible with electronic cards (5 V ± 12 V, etc.).

On the other hand, the prior art computer systems, such as that represented in FIG. 2, are most often supplied by centralized "Uninterruptible Power Supplies" 17. These power supplies include, for example, a static converter 18, converters 19 and 20 and a 400 volt battery 21. In the equipment 22, power boards 23 and 23 ′ directly supply the DC voltages useful to the electronics ( 5 V, ± 12 V, ...), from 230 volts AC.

• des inconvénients d'ordre technique :
  • . Dans les systèmes de télécommunication, la nécessité de procéder à une conversion tension alternative-tension continue, pour alimenter une réserve d'énergie électrique sous la tension 48 volts, réduit le rendement de la chaîne d'énergie de 10 à 20 %. De plus la tension 48 volts,qui est utilisée pour téléalimenter les terminaux téléphoniques,ne sera plus adaptée aux futurs terminaux numériques.
  • . Les alimentations sans interruption qui alimentent les systèmes informatiques disposent en général de contacteurs statiques qui garantissent le basculement dans les meilleures conditions entre l'alimentation directe par le réseau public et l'alimentation filtrée via les redresseurs d'entrée suivi des onduleurs de sortie. Pour protéger le système contre les transitoires de basculement et offrir un niveau plus élevé de filtrage du réseau, ce dernier mode de fonctionnement est forcé en permanence. Ainsi, le rendement et la fiabilité sont ceux de ces trois niveaux de conversion mis en série. Ils sont alors nettement insuffisants pour l'alimentation de systèmes sensibles.
• des inconvénients d'ordre économique :
  • . Les équipements mis en place pour la conversion tension alternative-tension continue sont dimensionnés pour satisfaire la puissance appelée par le système alimenté et sont par conséquent coûteux.

If these systems of the known art provide great security of supply by freeing the systems supplied from the vagaries of the supply of the alternating primary voltage, they nevertheless have numerous drawbacks.

• technical disadvantages:
  • . In telecommunication systems, the need to convert from alternating voltage to direct voltage, to supply a reserve of electrical energy at 48 volts, reduces the efficiency of the energy chain by 10 to 20%. In addition, the 48-volt voltage, which is used to power the telephone terminals, will no longer be suitable for future digital terminals.
  • . The uninterruptible power supplies that supply IT systems generally have static contactors which guarantee the best possible switching between direct supply via the public network and filtered supply via the input rectifiers followed by the output inverters. To protect the system against failover transients and provide a higher level of network filtering, this latter mode of operation is permanently forced. Thus, the efficiency and reliability are those of these three conversion levels put in series. They are then clearly insufficient for the supply of sensitive systems.
• economic disadvantages:
  • . The equipment installed for the conversion from alternating voltage to direct voltage is sized to meet the power demanded by the powered system and is therefore expensive.

STATEMENT OF THE INVENTION

The subject of the invention is the production of a distributed storage supply system allowing the supply of sensitive electronic systems through a single conversion level in normal operation.

• au moins un circuit d'alimentation à réserve d'énergie courte durée associé à chaque système alimenté,
• un circuit d'alimentation à réserve d'énergie moyenne durée ayant un délai de réaction inférieur au délai d'autonomie du circuit d'alimentation à réserve d'énergie courte durée.

The invention proposes, for this purpose, a supply system, with continuously distributed storage, of systems with sensitive functioning, characterized in that it comprises:

• at least one short-term power reserve supply circuit associated with each supplied system,
• a medium-duration power reserve supply circuit having a reaction time less than the autonomy period of the short-term energy reserve supply circuit.

Advantageously, the medium-duration power reserve supply circuit comprises an inverter operating in parallel ("off-line" mode).

• un circuit de redressement et de filtrage,
• un circuit de conversion,
• un circuit de filtrage ;

une chaîne de secours comprenant :

• un circuit de stockage,
• un circuit de régulation,
• un circuit de charge du circuit de stockage ;

et un circuit de contrôle/commande de chacun de ces différents circuits.Advantageously, a short-term energy reserve supply circuit successively comprises between its input and its output:

• a rectification and filtering circuit,
• a conversion circuit,
• a filtering circuit;

an emergency chain comprising:

• a storage circuit,
• a regulation circuit,
• a storage circuit charging circuit;

and a control / command circuit for each of these different circuits.

In the system of the invention thus characterized, the distribution of storage and the use of materials common to several techniques lead to a supply principle with very high reliability, to a reduced bulk and to easy maintenance.

In addition, the use of uninterrupted uninterrupted power supply supplemented by the implementation of a simplified operation compared to that adopted for the computer systems of the prior art allows a significant reduction in investment costs and of the energy chain. In addition, the short-term storage associated with the converters integrated in the powered systems does not entail any significant additional cost.

Compared to the systems of the known art, the system of the invention allows a cost saving of 20 to 30% in the systems considered from the distribution panel.

BRIEF DESCRIPTION OF THE DRAWINGS

• FIGS. 1 and 2 illustrate two systems of the prior art,
• FIG. 3 illustrates the system of the invention,
• FIG. 4 illustrates a short-term supply supply circuit of the system of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The power supply system, according to the invention, with continuously distributed storage of sensitive operating systems, which can be telecommunications systems or computer systems, is shown in FIG. 3. It comprises at least one power supply circuit with short-term energy reserve 30 associated with the system supplied and disposed as close as possible thereto, and a medium-duration energy reserve supply circuit 31, having a reaction time less than the autonomy time of the circuit short-term energy reserve supply circuit 30, this medium-duration energy reserve supply circuit 31 being located at the central level.

The distribution of electrical energy 10 and the backup source 11, which existed in the two devices of the prior art, have been shown with the same references.

The medium-duration energy storage circuit 31 is associated with an unmarked conversion device 33 placed on standby which is responsible for supplying the alternating voltage while waiting for the start-up of the long-term emergency power source 11.

Thus, if the network is cut for a few minutes, each short-term power reserve supply circuit 30 (less than 1 minute) becomes active to allow the electromechanical contactor 35 of the energy reserve supply circuit to switch. medium duration 31 (less than 1 hour), before starting the emergency source 11. This gives impeccable power quality (1 x 10 ^-6 ), supply circuits with short-term power supply duration filtering network micro-breaks, for example less than 300 ms.

• un transformateur de séparation 32 ayant pour objectif une grande sécurité des personnes, et la réalisation d'un premier filtrage des parasites de tous ordres émis par le réseau de distribution 10,
• un onduleur 33 fonctionnant en parallèle ou mode "off-line", associé à une batterie 34 qui permet d'obtenir l'autonomie en état de veille ,
• un contacteur électromécanique 35, par exemple de type ordinaire, permettant le basculement réseau-onduleur,
• une unité de commande 36 permettant de piloter ces différents éléments.

The medium-duration power reserve supply circuit, shown in FIG. 3, comprises:

• a separation transformer 32 having the objective of ensuring great safety for people, and carrying out a first filtering of parasites of all kinds emitted by the distribution network 10,
• an inverter 33 operating in parallel or "off-line" mode, associated with a battery 34 which allows autonomy to be obtained in standby state,
• an electromechanical contactor 35, for example of the ordinary type, allowing the switching from grid to inverter,
• a control unit 36 for controlling these various elements.

Advantageously, this medium-duration power reserve supply circuit 31 is produced by adapting an Uninterruptible Power Supply (UPS) optimized trade. In particular, the rectification-filtering function is limited to recharging the battery 34 after operation of the uninterruptible power supply following the interruption of the alternative distribution network 10.

• un circuit de redressement et de filtrage 40,
• un circuit de conversion 41,
• un circuit de filtrage 42.

As shown in FIG. 4, each short-term power reserve supply circuit 30 successively comprises between its input E (high voltage, alternating) and its output S (low voltage):

• a rectification and filtering circuit 40,
• a conversion circuit 41,
• a filtering circuit 42.

• un circuit de stockage 43,
• un circuit de régulation 44,
• un circuit de charge 45 du circuit de stockage 43 ;

et un circuit de contrôle/commande 46 de chacun de ces différents circuits.This circuit 30 also includes an emergency chain comprising:

• a storage circuit 43,
• a regulation circuit 44,
• a charging circuit 45 of the storage circuit 43;

and a control / command circuit 46 of each of these different circuits.

• Le circuit de redressement et de filtrage 40 :

In the following description, we will successively study each of these circuits.

• The rectification and filtering circuit 40:

• Le circuit de conversion 41 :
  Ce circuit peut être réalisé à l'aide d'un convertisseur continu du type 300 volts/5 volts continus de 200 Watts travaillant à des fréquences de découpage comprises entre 100 kHz et 1 MHz en fonction de la charge et offrant un rendement de 85 % à pleine charge. La plage de tension d'entrée s'étend de 200 volts à 400 volts.
• Le circuit de filtrage 42 :
  Des filtres et des circuits de protection disposés ici en sortie de chaque circuit 30, mais aussi en entrée, limitent les niveaux de perturbations (sortantes ou entrantes) et isolent le système à alimenter en cas de défaillance.
• Le circuit de stockage 43 :
  Ce circuit 43 peut être réalisé à l'aide d'une batterie organisée par exemple en deux branches de cinq éléments de 1,2 V chacun, afin d'obtenir 6 V en sortie. Cette organisation en deux branches permet de n'avoir que 15 A de courant dans chaque branche ainsi qu'une redondance du stockage. Ainsi, en cas de défaillance de l'une des branches, l'autre peut assurer l'alimentation, l'autonomie étant divisée par plus de deux, mais restant supérieure à quelques minutes.
• Le circuit de régulation 44 :
  Dans l'exemple de réalisation considéré ci-dessus, la tension aux bornes de chaque branche de batterie peut varier de 8 V en charge à 5 V en fin de décharge. Or, il faut fournir en décharge une tension constante de 5,15 V en sortie, d'où la nécessité d'un régulateur pour chaque batterie.

This circuit delivers a voltage between 200 V and 400 V. This circuit makes it possible to maintain the operation of the system supplied a few minutes after a cut of the alternating voltage E and to filter the rectified voltage. It may consist, in a manner known to those skilled in the art, of a diode bridge charging a bank of capacitors. The inrush current, when charging these capacitors can be limited by variable resistors with coefficient positive temperature (PTC). Once charging is complete, the average current decreases and the resistance of the PTCs becomes negligible in the circuit. Upstream of the diode bridge, an LC filter can reduce the reinjection of differential and common-mode disturbances.

• The conversion circuit 41:
  This circuit can be produced using a 300 volt / 5 volt DC 200 Watt continuous converter working at switching frequencies between 100 kHz and 1 MHz depending on the load and offering an efficiency of 85%. fully loaded. The input voltage range is from 200 volts to 400 volts.
• The filtering circuit 42:
  Filters and protection circuits arranged here at the output of each circuit 30, but also at the input, limit the levels of disturbance (outgoing or incoming) and isolate the system to be supplied in the event of failure.
• The storage circuit 43:
  This circuit 43 can be produced using a battery organized for example in two branches of five elements of 1.2 V each, in order to obtain 6 V at output. This organization in two branches makes it possible to have only 15 A of current in each branch as well as a redundancy of the storage. Thus, in the event of failure of one of the branches, the other can provide power, the autonomy being divided by more than two, but remaining greater than a few minutes.
• The regulation circuit 44:
  In the embodiment considered above, the voltage at the terminals of each battery branch can vary from 8 V on charge to 5 V at the end of dump. However, a constant voltage of 5.15 V must be supplied as a discharge, hence the need for a regulator for each battery.

• Le circuit de charge 45 du circuit de stockage 43 :

As known to those skilled in the art, one or more MOS transistors can be used to carry out such regulation, the transductance characteristic of which is considered in order to vary the drain-source voltage. In this case, a differential amplifier can amplify the difference between the reference voltage, obtained from a zener diode, and the voltage actually measured at the output of the conversion circuit 41. The reference voltage can be brought to zero by a microprocessor or by a voltage presence detector thus inhibiting the action of the regulator. During power outages, it is the latter circuit that regulates the output voltage in discharge, while the microprocessor limits the duration.

• The charging circuit 45 of the storage circuit 43:

• . Le mode floating consiste à charger en permanence le circuit 43 sous un courant faible, quel que soit l'état de celui-ci (chargé ou déchargé). Un des gros inconvénients de cette méthode est que l'on accélère le vieillissement des éléments de ce circuit 43 par surcharge permanente.
• . La charge rapide consiste à charger le circuit 43 sous fort courant (par exemple 4 Ampères) pendant une heure. Cette technique a l'avantage de recharger rapidement ce circuit 43, mais en accélère le vieillissement au même titre que la méthode précédente.
• . La troisième solution, qui peut être avantageusement retenue, consiste à effectuer une charge lente, sous faible courant (par exemple 0,4 Ampère) pendant une durée par exemple de 16 heures. Le MTBF ("mean time before failure") du réseau EDF étant nettement supérieur à 16 heures, ceci laisse largement le temps de recharger le circuit 43 avant d'être en présence d'une nouvelle coupure secteur. Afin de satisfaire au critère de redondance du système dans l'exemple considéré plus haut, chaque branche de batteries dispose de son chargeur. Chaque chargeur consiste par exemple en une petite alimentation à découpage dont la contre-réaction est un asservissement en courant. On obtient donc un générateur de courant, celui-ci pouvant varier de 0 à 0,7 A. Ce générateur est un hacheur-élévateur de tension à découpage travaillant depuis le 5,15 V pour recharger les batteries. La tension aux bornes de chaque branche de batteries peut atteindre 8 V en fin de charge. Une télécommande peut être prévue afin de pouvoir piloter la recharge à partir du microprocesseur.

• le circuit de contrôle/commande 46 :

This circuit can use one of the three charging techniques for a Nickel-Cadmium battery; floating mode, fast charge or slow charge:

• . The floating mode consists in permanently charging the circuit 43 under a weak current, whatever the state of the latter (charged or discharged). One of the major drawbacks of this method is that the aging of the elements of this circuit 43 is accelerated by permanent overload.
• . Fast charging consists of charging circuit 43 under high current (for example 4 Amps) for one hour. This technique has the advantage of quickly recharging this circuit 43, but accelerates its aging in the same way as the previous method.
• . The third solution, which can be advantageously adopted, consists in carrying out a slow charge, under low current (for example 0.4 amperes) for a duration for example of 16 hours. The MTBF ("mean time before failure") of the EDF network being clearly greater than 16 hours, this leaves plenty of time to recharge the circuit 43 before being in the presence of a new power outage. In order to satisfy the system redundancy criterion in the example considered above, each branch of batteries has its charger. Each charger consists for example of a small switching power supply whose feedback is a current control. We therefore obtain a current generator, which can vary from 0 to 0.7 A. This generator is a chopper-step-up voltage chopper working from 5.15 V to recharge the batteries. The voltage at the terminals of each battery branch can reach 8 V at the end of the charge. A remote control can be provided in order to be able to control recharging from the microprocessor.

• the control / command circuit 46:

This circuit can be realized by a microcontroller, which allows to have under a reduced volume a significant computing power and a great flexibility for the control and the monitoring. In addition, it facilitates the subsequent addition of new functions.

• détection d'absence du secteur,
• entretien des batteries utilisées : par exemple une heure de charge à 0,4 (A) par jour,
• charge proportionnelle à la durée de décharge : $$\text{T(h) = (t/600)*(I/30)*16}$$
  
• détection des défauts du circuit de stockage 43 ; par exemple celui des blocs de batteries : $$\text{tension < 6 V}$$
  
• contrôle du courant et de la tension de sortie : $$\text{Vs < Vo - 10 \% ou Vs > Vo + 20 \%}$$
  
• affichage de la tension et du courant de sortie.

The tasks performed by this circuit 46 are as follows:

• sector absence detection,
• maintenance of the batteries used: for example one hour of charging at 0.4 (A) per day,
• charge proportional to the duration of discharge: $$\text{T (h) = (t / 600) * (I / 30) * 16}$$
  
• detection of faults in the storage circuit 43; for example that of the battery packs: $$\text{voltage <6 V}$$
  
• output current and voltage control: $$\text{Vs <Vo - 10\% or Vs> Vo + 20\%}$$
  
• display of output voltage and current.

• tension secteur : 0 à 20 V (elle est prise après un transformateur),
• tension batteries : 0 à 8 V
• tension de sortie : 5,15 V
• courant de sortie (mesure d'une tension aux bornes d'un shunt) : 50 mV.

The analog-digital conversion carried out by the system of the invention is carried out with respect to an adjustable external reference voltage. The measurements to be taken by circuit 46 are quite disparate:

• mains voltage: 0 to 20 V (taken after a transformer),
• battery voltage: 0 to 8 V
• output voltage: 5.15 V
• output current (measurement of a voltage across a shunt): 50 mV.

Such a circuit 46 advantageously comprises a central unit 47, a random access memory 48 and a display 49.

The detection of the absence of the mains must allow the connection of the conversion circuit 41 to the storage circuit 43 in the event of the alternating source being cut off and vice versa in the event of restoration. In a manner known to those skilled in the art, this function can be carried out using threshold detectors. In addition, the role of this circuit 46 is to monitor if no fault appears on the conversion circuit 41 of a faulty battery. To check all these parameters, measurements are taken at the output of the conversion circuit 41.

• tester la présence secteur,
• effectuer la conversion de la tension de sortie,
• voir si elle n'est pas hors normes,
• effectuer la conversion du courant de sortie,
• écrire en mémoire la tension et le courant,
• détecter un défaut éventuel du circuit de stockage 43.

The control / command circuit 46 can operate according to a very simple algorithm comprising a main loop, which can include the following steps repeating indefinitely:

• test the sector presence,
• convert the output voltage,
• see if it is not out of the ordinary,
• convert the output current,
• write the voltage and current in memory,
• detect a possible fault in the storage circuit 43.

• . La première interruption peut être chargée de gérer la mise en marche des charges journalières du circuit de charge 45, de calculer le temps de recharge du circuit de stockage 43 en fonction du temps de décharge, et de gérer les recharges.
• . La deuxième interruption peut être chargée de rafraichir l'afficheur 49.
• . La troisième interruption peut être une interruption externe, déclenchée par l'utilisateur si celui-ci désire visualiser un défaut. En effet, si un défaut a été relevé par le circuit 46, il suffit à l'utilisateur d'appuyer, par exemple, sur un bouton poussoir pour visualiser la nature de celui-ci sur l'afficheur 49.

This circuit 46 can also include two clock overflow interrupts and an external interrupt:

• . The first interruption can be responsible for managing the starting of the daily charges of the charging circuit 45, for calculating the recharging time of the storage circuit 43 as a function of the discharge time, and for managing the recharges.
• . The second interruption can be responsible for refreshing the display 49.
• . The third interruption can be an external interruption, triggered by the user if he wants to view a fault. Indeed, if a fault has been detected by the circuit 46, the user need only press, for example, a push button to view the nature of the latter on the display 49.

Advantageously, the short-term power reserve supply 30 uses a circuit conversion 41 continuous / continuous at very high energy density which has a good efficiency. This voltage converter can therefore be installed on a printed circuit and its thermal losses can then be removed by thermal convection by means of a suitable cooling device. This conversion circuit 41 also provides galvanic isolation between the high voltage AC network (input E) and the low voltage output (output S). It must offer a high rate of regulation of the output voltage S as a function of the fluctuations of the input voltage E and the load variations.

To this conversion circuit 41 is associated a short-term energy storage circuit 43, rechargeable several hundred times after use. The discharge of this storage device 43 occurs when the system of the invention switches over to the medium-duration energy storage circuit 31.

Advantageously, this short-term storage device 30 can use undersized sealed storage batteries. Such batteries can deliver a very large power, provided that the storage time is limited to protect them from any irreversibility. Such an arrangement is very economical. This storage could also be carried out using very high capacity capacitors (several Farads), in a reduced volume and capable of delivering a current of a few tens of amperes.

The short-term emergency chain, consisting of storage circuits 43, regulation 44 and charging 45 has the originality of being connected at a single point: at the output of the conversion circuit 41. This circuit 41 can therefore be of a common model and can evolve independently. The emergency chain draws the load power from the storage circuit 43 on the output of the circuit 41 to its normal voltage. The role of the charging circuit 45 is to make this output voltage compatible with the recharging of the storage circuit 43. It can be, for example, a non-isolated switching voltage booster with limited current. The coupling comes into operation as soon as the output voltage of the conversion circuit 41 crosses a low threshold. The commissioning of a coupling circuit can be anticipated by observing a low level on the input voltage. The object of such a circuit is to maintain a constant output voltage during discharge and to limit the duration of discharge. As soon as the output voltage of the conversion circuit 41 is restored, the discharge is interrupted. Advantageously, this coupling device can be produced in a simple manner using a transistor controlled by a linear regulator itself controlled by output and input voltage comparators, and a discharge duration timer. To reduce the voltage drop to the minimum (a few tens of mV) at high current (a few tens of amps), it is advantageous to use a low voltage MOSFET transistor, with very low internal resistance in conduction.

In a particular embodiment, the short-term reserve power supply circuit 30 is a 230 V / 5 V 30 A power reserve power supply offering autonomy of 5 to 10 minutes on battery.

In normal operation, the high AC voltage of the network is directly converted into a DC output voltage by the conversion circuit. 41 main energy which can provide isolation between the input E and the output S. Secondary voltages S 'can be obtained by other converters 16 using the main output voltage.

In emergency operation, the storage circuit 43 maintains, via the regulation circuit 44, a constant output voltage for a voluntarily limited time, so as not to reduce the life of the storage circuit 43.

When normal operation is restored, the charging circuit 45 is started until the storage circuit 43 is fully charged.

Reliability considerations concerning this storage circuit 43 can lead to doubling the backup chain.

In this exemplary embodiment, the vital functions are built in unprogrammed electronics, while those of high level are processed by a microcontroller which, moreover, provides information via the display 49 on the state of the system of the invention.

Several improvements to the short-term reserve supply circuit are possible. Namely, to extend monitoring as well as to add a role of saving the measured data so that it can be read remotely via a remote management network.

Each storage circuit 43 may include modularly designed battery branches: chargers, regulators and batteries. The conversion circuit 41 itself can be a power supply module already designed to operate in parallel with other modules. We can therefore easily increase the power if necessary.

By way of example, for a medium-capacity telecommunications system connected to 30,000 subscribers, the system of the invention may include around one hundred short-term power supply supply circuits 30 of 200 Watts each.

Claims (3)

1. An uninterrupted, distributed storage supply system for sensitively operating systems supplied from the public electric energy distribution mains (10) or an emergency power supply (11) producing an equivalent voltage, characterized in that it comprises at least one short term energy reserve supply circuit (30) associated with each supplied system and a medium term energy reserve supply circuit 31 having a reaction delay shorter than the autonomy delay of the short term energy reserve supply circuit.
2. System according to claim 1, characterized in that the medium term energy reserve supply circuit (31) comprises a wiggler (33).
3. System according to either of the claims 1 and 2, characterized in that a short term energy reserve supply circuit (30) successively comprises between its input (E) and its output (S) a rectifying and filtering circuit (40), a conversion circuit (41), a filtering circuit (42), an emergency chain incorporating a storage circuit (43), a regulating circuit (44), a charging circuit (45) for the storage circuit (42) and a conttrol/checking circuit (46) for each of the aforementioned circuits.

Images